Complete hematopoietic reconstitution following ablative radiation and/or chemotherapy has been achieved in dogs using stem cells isolated from non-leukemic peripheral blood. This has yet to be achieved in humans. This research project would involve collection characterization and storage of hematopoietic stem cells from peripheral blood of normal human individuals. It will combine the disciplines of blood banking, in which cytapheresis was developed; hematology, in which cell culture techniques have been developed; and immunology, in which surface characterization studies have evolved. An optimum collection technique using the microprocessor-controlled Fenwal CS 3000 blood cell separator to collect a monoculear cell product rich in hematopoietic stem cells would be the first step. The product so collected will be monitored with various in vitro stem cell culture techniques, as well as various studies that will delineate the surface and antigenic characteristics of the cells collected. Techniques for storing these cells will also be investigated. The currently used bone marrow technique of storage with dimethylsulfoxide after controlled rate freezing in liquid nitrogen will be developed specifically for use for peripheral stem cells. The long-term objective of transfusion into humans to achieve complete hematopoietic reconstitution may or may not be achieved during the five-year period of this study. Eventual long-term use of these peripheral stem cells may be used to treat a variety of disorders, including various forms of cancer, both solid tumors and hematologic malignancies, and aplastic anemia. This would be a vast improvement over the current technique of collecting bone marrow during an operation.